DS2282/87-22282-000 Maxim Integrated, DS2282/87-22282-000 Datasheet - Page 14

• Manufacturer Part Number: DS2282/87-22282-000
• Description: Network Controller & Processor ICs
• Manufacturer: Maxim Integrated

Specifications of DS2282/87-22282-000

• Supply Current (max): 30 mA
• Maximum Operating Temperature: + 70 C
• Mounting Style: Through Hole
• Package / Case: SIL-30
• Minimum Operating Temperature: 0 C
• Operating Supply Voltage: 5 V
• Part # Aliases: 90-22820-000

necessary data to create a PRM from both the monitor
registers and from the SLIP signal. It creates the open-
ing and closing flags as well as the address and control
bytes. Once the PRM packet has been assembled, the
DS2282 will generate CRC–16 and include it at the end
of the PRM. And finally, before the PRM is sent, zeros
are inserted to insure that none of the PRM data ap-
pears as a flag.
Receive Unscheduled Message Operation
The DS2282 decodes incoming unscheduled mes-
sages as they are received. The DS2282 will report the
received unscheduled message via the RUMR when
the message has been received for three consecutive
times. This integration allows the DS2282 to operate
properly even on high bit error rate lines. The RUMR is
cleared when read via the serial port. The INT pin will be
asserted (transitions low), indicating to an external con-
troller that an unscheduled message has been received
three consecutive times. The user may count incoming
unscheduled messages by monitoring the INT pin. The
INT pin will return high as soon as the RUMR is ac-
cessed.
Two output signals on the DS2282 will respond to cer-
tain unscheduled messages. The PLB (Payload Loop-
back) signal will transition high if the code word for pay-
load loopback activate (001010) is received three times.
It will remain high until the DS2282 has received the
payload loopback deactivate code word (011001) three
times. The LLB (Line Loopback) signal operates simi-
larly. The LLB signal will transition high when the
DS2282 has received the code word for line loopback
activate (000111) three times. It will remain high until the
DS2282 has received the code word for line loopback
deactivate (011100) three times. The user has the op-
tion to control the PLB and LLB pins via the Loopback
Control Register (LBCR); see “Loopback Control Regis-
ter.”
RUMR: Receive Unscheduled Message
Register (18)
NA
DS2282
022798 14/22
(MSB)
NA
NA
CW5
Not Assigned. Could be any value when
read.
CW4
CW3
CW2
CW1
CW0
(LSB)
NA
CW5
CW0
Transmit Unscheduled Message Operation
The DS2282 will transmit outgoing unscheduled mes-
sages. The DS2282 will continuously transmit the un-
scheduled message described in TUMR if enabled via
the TUM bit in the TUMR. If unscheduled messages are
being transmitted, all PRMs are superseded. When the
TUM is cleared, the DS2282 will finish sending the un-
scheduled message that it is currently transmitting be-
fore switching to either the idle code or PRMs.
TUMR: Transmit Unscheduled Message
Register (19)
TUM
CW5
CW0
PAR: PRM Address Register (1F).
allows the user to set the PRM opening address C/R bit
depending on the source of the PRM. The C/R bit is set
to zero for PRMs created by user equipment such as a
CPE or set to one for PRMs created by a carrier. The
PAR allows the user to control the expected state of the
C/R bit as well as control the state of the bit in the PRMs
created by the DS2282.
TC/R
RC/R
(MSB)
(MSB)
TUM
0
0
0
Transmit PRM C/R Bit Control
0=force C/R bit to zero in outgoing PRM
1=force C/R bit to one in outgoing PRM
Receive PRM C/R Bit Control
0=only respond to RPM with the C/R bit set
to zero
1=only respond to PRM with the C/R bit set
to one
Not Assigned. Could be any value when
read.
MSB of the Receive Unscheduled Mes-
sage Code word.
LSB of the Receive Unscheduled Mes-
sage Code word.
CW5
Transmit Unscheduled Message Enable
MSB of the Transmit Unscheduled Mes-
sage Code word.
LSB of the Transmit Unscheduled Mes-
sage Code word.
0
CW4
0
CW3
0
CW2
0
The DS2282
TC/R
CW1
RC/R
CW0
(LSB)
(LSB)